The first three waves of the new Health and Retirement Study (HRS) will be used to estimate a well-specified dynamic, discrete choice, utility-maximizing model. The proposed research will examine how a- complex set of factors, including health status, job characteristics, health insurance, and beliefs about future uncertain events, interact to determine the labor decisions of individuals during the later part of their working lives. The HRS data, along with recent advances in estimation techniques and available computing power, make it possible to estimate a detailed model which can examine many of the specific retirement issues which are important to developing a better understanding of the retirement process as a whole. Health status has been found to be an important part of the labor Supply decisions made by older workers. Therefore, using newly developed estimation techniques, the proposed research will carefully model a detailed, endogenous process describing an individual's beliefs about future health status. This will allow the model to thoroughly examine how current health status and concerns about future health status affect an individual's attitudes and decisions regarding different types of job offers. The HRS facilitates this analysis by allowing a particular job to be described by a large set of non-pecuniary working conditions, as well as a set of pecuniary characteristics. Important realism is added to the model by allowing the individual to take into account that the individual job characteristics which compose the job offers that he receives are not independently determined. The structural nature of the model will be exploited to simulate the labor supply effects of changes in government programs, changes in legislation affecting the availability of health insurance, and changes in the overall health of the older population. The detail devoted to realistically modeling beliefs about future health status and job offers should allow better predictions of individual behavior.